// base64加密 解密

/* //1.加密
 var result = Base.encode('125中文');  //--> "MTI15Lit5paH"

 //2.解密
 var result2 = Base.decode(result); //--> '125中文'
 */
// function ff(root, factory) {
//     if (typeof define === "function" && define.amd) {
//         define([], factory);
//     } else if (typeof module === "object" && module.exports) {
//         module.exports = factory();
//     } else {
//         root.Base = factory();
//     }
// }
//
// const Base = ff(this, function () {
//     'use strict';
//
//     var Base = new Base64();
//     return Base;
// })
// console.log(Base);
// console.log(ff);

function Base64() {

    // private property
    this._keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
}

// public method for encoding
Base64.prototype.encode = function(input) {
    let output = '', chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
    input = this._utf8_encode(input);
    while (i < input.length) {
        chr1 = input.charCodeAt(i++);
        chr2 = input.charCodeAt(i++);
        chr3 = input.charCodeAt(i++);
        enc1 = chr1 >> 2;
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
        enc4 = chr3 & 63;
        if (isNaN(chr2)) {
            enc3 = enc4 = 64;
        } else if (isNaN(chr3)) {
            enc4 = 64;
        }
        output = output +
            this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
            this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
    }
    return output;
}

// public method for decoding
Base64.prototype.decode = function(input) {
    let output = '', chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0;
    input = input.replace(/[^A-Za-z0-9+/=]/g, '');
    while (i < input.length) {
        enc1 = this._keyStr.indexOf(input.charAt(i++));
        enc2 = this._keyStr.indexOf(input.charAt(i++));
        enc3 = this._keyStr.indexOf(input.charAt(i++));
        enc4 = this._keyStr.indexOf(input.charAt(i++));
        chr1 = (enc1 << 2) | (enc2 >> 4);
        chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
        chr3 = ((enc3 & 3) << 6) | enc4;
        output = output + String.fromCharCode(chr1);
        if (enc3 != 64) {
            output = output + String.fromCharCode(chr2);
        }
        if (enc4 != 64) {
            output = output + String.fromCharCode(chr3);
        }
    }
    output = this._utf8_decode(output);
    return output;
}

// private method for UTF-8 encoding
Base64.prototype._utf8_encode = function(string) {
    string = string.replace(/\r\n/g, '\n');
    let utftext = '';
    for (let n = 0; n < string.length; n++) {
        let c = string.charCodeAt(n);
        if (c < 128) {
            utftext += String.fromCharCode(c);
        } else if ((c > 127) && (c < 2048)) {
            utftext += String.fromCharCode((c >> 6) | 192);
            utftext += String.fromCharCode((c & 63) | 128);
        } else {
            utftext += String.fromCharCode((c >> 12) | 224);
            utftext += String.fromCharCode(((c >> 6) & 63) | 128);
            utftext += String.fromCharCode((c & 63) | 128);
        }

    }
    return utftext;
}

// private method for UTF-8 decoding
Base64.prototype._utf8_decode = function(utftext) {
    let string = '', i = 0, c = 0, c2 = 0, c3 = 0; // c1 = 0
    while (i < utftext.length) {
        c = utftext.charCodeAt(i);
        if (c < 128) {
            string += String.fromCharCode(c);
            i++;
        } else if ((c > 191) && (c < 224)) {
            c2 = utftext.charCodeAt(i + 1);
            string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
            i += 2;
        } else {
            c2 = utftext.charCodeAt(i + 1);
            c3 = utftext.charCodeAt(i + 2);
            string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
            i += 3;
        }
    }
    return string;
};
let Base = new Base64();
export {
    Base
}
